Combined Cycle Power Plant Expansion Joint Failure

Engineers design systems based on the best available information about the design conditions. These design conditions are based on a reasonable understanding about how systems will be operated and the pressures and temperatures expected. This paper focuses on the failure of an expansion joint in a hot water system at a combined cycle power plant. The root cause of the failure can be traced to the way the plant was operated. The operation of the plant produced temperatures and pressures that were well beyond the design basis of the expansion joint and the system in which it was used. This failure highlights some considerations in setting the design temperature and pressure for hot water systems, and for the operation of these systems.